The present invention relates to low resistance value metal strip resistors and a method of making the same.
Metal strip resistors have previously been constructed in various ways. For example, U.S. Pat. No. 5,287,083 to Zandman and Person discloses plating nickel to the resistive material. However, such a process places limitations on the size of the resulting metal strip resistor. The nickel plating method is limited to large sizes because of the method for determining plating geometry. In addition, the nickel plating method has limitations on resistance measurement at laser trimming.
Another approach has been to weld copper strips to the resistive material to form terminations. Such a method is disclosed in U.S. Pat. No. 5,604,477 to Rainer. The welding method is limited to larger size resistors because the weld dimensions take up space.
Yet another approach has been to clad copper to the resistive material to form terminations such as disclosed in U.S. Pat. No. 6,401,329 to Smjekal. The cladding method is limited to larger size resistors because of tolerances in the skiving process used to remove copper material thus defining the width and position of the active resistor element.
Still further approaches are described in U.S. Pat. No. 7,327,214 to Tsukada, U.S. Pat. No. 7,330,099 to Tsukada, and U.S. Pat. No. 7,326,999 to Tsukada. Such approaches also have limitations.
Thus, all of the methods described have one or more limitations. What is needed is a small sized low resistance value metal strip resistor and a method for making it.